Synthesis and Properties of Fluorocarbon–Hydrocarbon Hybrid Block Copolymers with Perfluorosulfonimide Acid

[Image: see text] Novel fluorocarbon–hydrocarbon hybrid block copolymer electrolytes were synthesized. The block copolymer electrolytes consist of poly(perfluoropropyl sulfonimide) (PC3SI) as a perfluorinated hydrophilic segment and poly(ether ether sulfone) as a hydrocarbon hydrophobic segment. The sulfonimide group of poly(perfluoropropyl sulfonimide) has superacidity, very low equivalent weight (EW = 293 g/equiv), and a proton conductivity of 1.2 × 10(–2) S/cm under dry conditions and 25 °C, although soluble in water. The proton conductivity of the block copolymer was 1.7 × 10(–3) S/cm at 20% relative humidity and 25 °C, which is three times as high as that of Nafion 112.